This invention relates to methods and apparatuses for removing material from discrete areas on a semiconductor wafer, and in particular to methods and apparatuses for removing material from over alignment marks on a wafer.
It is sometimes desirable in semiconductor device manufacturing to remove material from over discrete wafer areas, without exposing other wafer areas to the etchant solutions. One type of discrete area includes alignment marks which are used to align wafers during processing. Alignment marks are preferably kept substantially clear of contaminants or material so that processing equipment can easily locate them. Alignment marks can get covered with a variety of material including photoresist, etched substrate material, and chemical mechanical polishing slurry or a variety of thin films. When alignment marks get covered with material, it is desirable to remove the material. Methods and apparatuses for removing material from over alignment marks are described in U.S. Pat. No. 5,271,798, which is assigned to the assignee of this document, the disclosure of which is incorporated by reference.
This invention arose out of concerns associated with providing improved methods and apparatuses for removing material from discrete areas, e.g. alignment marks, on a semiconductor wafer.
Methods and apparatuses for removing material from discrete areas on a semiconductor wafer are described. In one implementation, an etchant applicator is provided having a tip portion. Liquid etchant material is suspended proximate the tip portion and the etchant applicator is moved, together with the suspended liquid, sufficiently close to a discrete area on a wafer to transfer liquid etchant onto the discrete area. In various embodiments the tip portion can comprise fluid permeable materials, fluid-absorbent materials, and/or wick assemblies. An exhaust inlet can be provided operably proximate the tip portion for removing material from over the wafer. The tip portion can be moved to touch the discrete area.